Two out of three voting solenoid arrangement

ABSTRACT

A binary voting solenoid arrangement  10  is provided which operates in a “2 out of 3” manner to provide relatively high safety, low spurious tripping and a relatively low installation cost, while also enabling on-line testing of each solenoid individually without process interruption. Solenoid arrangements  10, 10′  and  10″  are preferably used in a three-way configuration, while solenoid  10″′  may be used in a two-way configuration.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/638,311, entitled Two Out Of Three VotingSolenoid Arrangement, filed Aug. 14, 2000, which is a Continuation ofU.S. patent application Ser. No. 09/233,406, entitled Two Out Of ThreeVoting Solenoid Arrangement, filed Jan. 19, 1999.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to solenoid valves, and more particularlyto an arrangement of solenoid valves in instrumentation and processcontrol systems of a plant.

[0004] 2. Background Information

[0005] Modern process or manufacturing plants contain innumerableoperating components. These components are tied together to form systemscontrolled by instrumentation and control systems containing sensors andcontrollers. The instrumentation and control systems on such plants notonly serve to control the functions of the various components in orderto achieve the desired process conditions, but they also provide thefacility to safely modify or discontinue the operation of all or aportion of the plant's systems in order to avoid an unsafe situation orcondition.

[0006] Safety systems or configurations require routine testing in orderto verify that they continue to properly perform the functions for whichthey were intended. From an operational and economic point of view, theyalso should not modify or discontinue the operation of the plant systemunnecessarily. One of the means by which such safety systems function isby the securing or diverting of the supply of a certain process fluid orthe supply of motive power to a plant system or component of a plantsystem.

[0007] One of the means by which these safety functions may beaccomplished is through the use of solenoid operated valves. Inoperation, the solenoid valves of such systems serve to isolate and/orvent off the fluid or pneumatic source from the system when the solenoidvalve changes state or position (e.g. when the valve is de-energized byswitches or process monitoring sensors coupled thereto). The plantsystem and any system controlled thereby is then placed in aconfiguration designated for safety.

[0008] In many cases, the operation of individual solenoid valves maynot be tested without actually tripping the system and undesirablymodifying or discontinuing the operation of the plant system. Moreover,various configurations available for actuating safety shutoff valvesgenerally require a trade-off between competing characteristics ofsafety and spurious trip rate.

[0009] For example, a “1 out of 2” voting solenoid valve arrangementgenerates a process modification (i.e. shutdown) when at least one ofthe two solenoids changes state. Such a configuration providesrelatively high safety, with an associated relatively high spurious triprate (i.e., a single faulty valve or sensor may generate a false trip).

[0010] A “2 out of 2” voting solenoid valve arrangement requiresactuation of two solenoid valves in order to trigger a modification ofthe plant system. This configuration has a relatively low spurious triprate, since both solenoids must fail or otherwise change state togenerate a spurious trip. However, the solenoid valves of thisarrangement must be tested frequently to insure safety, since failure ofonly a single solenoid valve may effectively prevent the system fromshutting down, etc.

[0011] Quad voting solenoids provide a balance of safety andreliability, however the quad configuration utilizes four solenoids in arelatively complex arrangement that tends to be difficult to install,test, and maintain.

[0012] Thus, there exists a need for a voting solenoid configurationwhich combines the features of relatively high safety with relativelylow spurious trip rate and does not require the plant system to be shutdown during testing.

SUMMARY OF THE INVENTION

[0013] According to an embodiment of this invention, a voting solenoidarrangement is adapted to selectively couple a fluid supply with a fluidreceiver, the voting solenoid arrangement including first, second andthird solenoid valves disposed in fluid communication with one another,each of the solenoid valves being alternately actuatable between firstand second states so that a change of state of any two of the solenoidvalves is adapted to alternately couple and de-couple the fluid supplywith the fluid receiver.

[0014] Another aspect of the present invention includes a method forselectively coupling a fluid supply with a fluid receiver, the methodcomprising the steps of providing first, second and third solenoidvalves each being alternately actuatable between first and secondstates; and disposing the solenoid valves in fluid communication withone another so that a change of state of any two of the solenoid valvesis adapted to alternately couple and de-couple the fluid supply with thefluid receiver.

[0015] According to still another aspect, this invention includes a twoway valve including a voting solenoid arrangement adapted to selectivelycouple a fluid input with a fluid output, the voting solenoidarrangement including first, second and third solenoid valves disposedin fluid communication with one another, each of the solenoid valvesbeing alternately actuatable between first and second states so that achange of state of any two of the solenoid valves is adapted toalternately couple and de-couple the fluid input with the fluid output.

[0016] According to yet another aspect, this invention includes a methodfor fabricating a two-way valve for selectively coupling a fluid inputwith a fluid output, the method including providing first, second andthird solenoid valves, each being alternately actuatable between firstand second states, and disposing the solenoid valves in fluidcommunication with one another such that a change of state of at leastany two of the solenoid valves is adapted to alternately couple andde-couple the fluid input with the fluid output.

[0017] The above and other features and advantages of this inventionwill be more readily apparent from a reading of the following detaileddescription of various aspects of the invention taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a schematic circuit diagram of a fluid safety systemincorporating the solenoid arrangement of the present invention;

[0019]FIG. 2 is a truth table for individual actuation of the solenoidsof the solenoid arrangement of FIG. 1;

[0020]FIG. 3 is a view similar to FIG. 1, of an alternate embodiment ofthe present invention;

[0021]FIG. 4 is a view similar to FIG. 2, of the alternate embodiment ofFIG. 3;

[0022]FIG. 5 is a schematic circuit diagram of another alternateembodiment of the present invention;

[0023]FIG. 6 is a block diagram showing the solenoid arrangements of thepresent invention employed in (A) a three-way configuration and (B) atwo-way configuration; and

[0024]FIG. 7 is a schematic circuit diagram of an alternate embodimentof the present invention designed to be employed in a two-wayconfiguration;

DETAILED DESCRIPTION

[0025] Referring to the figures set forth in the accompanying Drawings,the illustrative embodiments of the present invention will be describedin detail hereinbelow. For clarity of exposition, like features shown inthe accompanying Drawings shall be indicated with like referencenumerals and similar features as shown in alternate embodiments in theDrawings shall be indicated with similar reference numerals.

[0026] Referring to FIGS. 1-4, the apparatus constructed according tothe principles of the present invention is shown. The present inventionincludes a voting solenoid arrangement 10 which operates in a “2 out of3” manner to provide relatively high safety, low spurious tripping and arelatively low installation cost, while also enabling on-line testing ofeach solenoid individually without process interruption. Solenoidarrangement 10 is preferably manifolded (not shown), to facilitatemaintenance on any detected failure, and to simplify installation andreplacement.

[0027] Referring now to FIG. 1, the apparatus of the present inventionwill be more thoroughly described. As shown, the voting solenoidarrangement 10 of the present invention is adapted to selectivelychannel air from an air supply 12 ultimately to a valve or other fluidreceiver 14. Valve 14 may be a component of a plant process,instrumentation or control system. Any suitable fluid may be utilized,such as hydraulic fluid, water, etc. In a preferred embodiment, thesolenoid arrangement 10 is pneumatic. The fluid is fed from air supply12 to solenoid arrangement 10 through conduit 16 and subsequently flowsfrom solenoid arrangement 10 to valve 14 through conduit 18. Votingsolenoid arrangement 10 includes three discreet solenoid valves 20, 22and 24, any two of which must be actuated to start or stop air flow fromconduit 16 to conduit 18. As shown, in a preferred embodiment, solenoidvalves 20, 22 and 24 are bidirectional 5-port 4-way solenoid valves.These valves are thus operable with fluid flowing therethrough in eitherof two directions along one of two pairs of alternate pathways. Forexample, valve 20 includes a pair of common ports 202 and 204 which areselectively and alternately coupled with a distinct two of three otherports by alternate fluid pathways 26 and 27. As shown, in a first state(i.e., energized), pathways 26 of valve 20 couple ports 202 and 204 toports 201 and 205. When actuated to its second (i.e. de-energized)state, pathways 27 (shown in phantom) couple the common ports 202 and204 with ports 201 and 203. Fluid communication or coupling operation ofthe pathways 26 and 27 are mutually exclusive, so that when pathways 26are open, pathways 27 are closed and vice versa.

[0028] Conduit 16 supplies air simultaneously to port 201 of valve 20and to port 225 of solenoid valve 22. When the valves 20, 22 and 24 arein their normal or energized states, the passageways 26 are open andpassageways 27 are closed. Alternatively, when the valves are disposedin their de-energized states, passageways 26 are closed and thealternate passageways 27 are open. When the valves are in their normalstate air will flow from conduit 16 through port 201 of valve 20 to port202 and to conduit 28 which in turn supplies the air to port 221 ofvalve 22. The air then travels through the valve 22 to port 222 and onthrough conduit 30 to port 241 of valve 24. Simultaneously, air fromconduit 16 is fed to conduit 32, to port 225 of valve 22, through thevalve to port 224, then to port 245 of valve 24 through conduit 34. Thesolenoid valve 24 then passes the air to port 244, to conduit 18 andultimately to valve 14.

[0029] In the event of a change of state of any single valve 20, 22 or24, such as in the event of a valve failure or a valve test, air willcontinue to pass through the solenoid arrangement 10 to the valve 14.For example, in the event solenoid valve 24 is de-energized, althoughair flowing through the valve from conduit 34 will be shut off,passageways 27 will open to permit air from conduit 30 to be fed fromport 241 to port 244, and thus to conduit 18, to maintain air flow tovalve 14. Air will only cease flowing to conduit 18 in the event one ofthe other solenoid valves 20 or 22 is also de-energized. In this regard,if valve 22 is de-energized in addition to valve 24, air being fed tothe valve 22 at port 221 would flow to port 224 (instead of port 222)and thus through conduit 34 to port 245 of the valve 24. Since valve 24is de-energized, passageway 26 thereof is closed and accordingly, airdoes not flow to conduit 18. Similarly, if both valves 20 and 24 arede-energized, air that would otherwise flow to port 241 of valve 24 fromvalve 22, is effectively shutoff at valve 20 due to the closing of thepassageway 26 between ports 201 and 202 thereof.

[0030] In the event that only valve 22 is de-energized, air supplyarriving at port 225 through conduit 32 at port 225 is effectively shutoff. However, air being supplied by conduit 28 to port 221 will beshunted to port 224 and thus through conduit 34 to port 245 of valve 24,where it will be fed through the valve to conduit 18. In the event thatboth valve 22 and valve 20 are de-energized, the air flow to valve 22through conduit 28 will be effectively shut off by the action of valve20 which when de-energized, shunts the air supply at port 201 to port204.

[0031] As also shown, a series of pressure valves 40, 42 and 44 areprovided to monitor the actual state of solenoid valves 20, 22 and 24.In a preferred embodiment, pressure switch 40 is disposed in pressuresensing contact with port 204 of solenoid valve 20. Pressure switch 42is disposed in pressure sensing contact with conduit 30 and pressureswitch 44 is disposed in pressure sensing contact with port 242 of valve24. The pressure switches 42 and 44 include electrical contacts (notshown) which are alternately open and closed in response to absence andpresence of pressure thereat (i.e normally open). Pressure switch 40includes electrical contacts (not shown) which are alternately closedand opened in response to absence and presence of pressure thereat (i.e.normally closed).

[0032] In the embodiment shown, when only solenoid valve 20 isde-energized, air pressure from port 201 is shunted to port 204 whichserves to open the contacts of switch 40. Simultaneously, the contactsof pressure switches 42 and 44 are opened due to lack of pressurethereat. Upon reset or energization of solenoid valve 20, the contactsof pressure switches 40, 42 and 44 return to their closed states. Whenonly solenoid valve 22 fails or otherwise toggles to its de-energizedstate, pressure switches 42 and 44 sense a decrease in pressure and opentheir contacts. Upon reset of solenoid valve 22, the contacts ofpressure switches 42 and 44 return to their closed states. When onlysolenoid valve 24 fails or is otherwise de-energized, pressure switch 44registers a reduction in pressure to open the contacts thereof. Uponreset of solenoid valve 24, the contacts of pressure switch 44 return toa closed state. This operation of pressure switches 40, 42 and 44 isshown in the truth table of FIG. 2.

[0033] The contacts of pressure switches 40, 42 and 44 may be connectedto suitable circuitry such as, for example, a programmable logiccontroller (PLC) which may be programmed using the truth table of FIG. 2in a manner familiar to those skilled in the art, to verify operation ofeach individual solenoid valve 20, 22 and 24 during testing thereof. Thepresent invention thus advantageously enables each solenoid valve to betested independently without disrupting fluid flow to valve 14. In thismanner, the solenoid arrangement 10 may be tested frequently withoutdisrupting plant process operation for increased safety relative toprior art configurations. In addition, safety is enhanced by effecting acessation of fluid flow to valve 14 upon de-energization of less than afull complement of the solenoid valves 20, 22 and 24, i.e., air flow isabated once any two of the three valves changes state. This effectivelypermits solenoid arrangement 10 to safely stop air flow even in theevent one of the valves 20, 22 and 24 fails in its energized state andbecomes non-operational. Such safety is achieved while advantageouslyproviding the low spurious trip rate typically associated withconventional 2 out of 2 voting solenoid arrangements by requiring twosolenoids to change state before terminating fluid flow.

[0034] As also shown in FIG. 1 a stack selector valve including valves50 and 52 may be used to bypass the solenoid arrangement 10 formaintenance and/or replacement thereof. As shown, valve 50 is disposedbetween fluid supply 12 and conduit 16 to selectively divert fluid flowfrom conduit 16 to a pressure switch 54. Valve 52 is connected to fluidor air supply 12 upstream of valve 50, and is coupled to both conduit 18and to valve 14 for selectively coupling air supply 12 directly to valve14 while bypassing voting solenoid arrangement 10. Where used herein“upstream” and “downstream” refer to the fluid flow direction relativeto components of the present invention. For example, the term“upstream”, when referring to a component, refers to a direction counterto the direction of fluid flow into or through the component, while“downstream” refers to the direction of fluid flow through thecomponent. Valves 50 and 52 of the stack selector valve are operable intandem with one another between a normal position in which air flowsfrom supply 12, through valve 50 to conduit 16, and from conduit 18through valve 52 to valve 14 as shown, and a bypass position as shown inphantom. In the bypass position, air flow bypasses solenoid arrangement10 and also supplies pressure to pressure switch 54, which serves tochange the state of (i.e. open) the contacts thereof. Pressure switch 54is preferably connected to monitoring and/or control circuitry such asthe PLC discussed hereinabove to facilitate monitoring the position ofvalves 50 and 52.

[0035] As shown and described herein, solenoid valves 20, 22 and 24 arepreferably disposed in their energized states during normal fluid flowthrough passageway 26 thereof to valve 14. This generally providesincreased safety, since any interruption in power to the solenoid valveswill tend to generate a change in state of the valves to stop fluid flowto valve 14. However, these solenoid valves may be disposed in theirde-energized state during normal fluid flow therethrough, withoutdeparting from the spirit and scope of the present invention. Similarly,although the contacts of pressure switches 42 and 44 are preferablydisposed in their open states and pressure switch 40 in the closed statewhen solenoid valves 20, 22 and 24 are de-energized, any, or all ofthese contacts may be disposed in their closed or open states when thevalves are de-energized, without departing from the spirit and scope ofthe present invention.

[0036] As also shown, in a preferred embodiment, ports 203 and 205 ofvalve 20, port 223 of valve 22, and port 243 of valve 24 are vented.However, these ports may be coupled to a fluid recovery system, such asin the event fluid other than air, (i.e. hydraulic fluid), is used,without departing from the spirit and scope of the invention.

[0037] Referring now to FIGS. 3 and 4 an alternate embodiment of thepresent invention is shown as voting solenoid arrangement 10′. It is inmany respects substantially similar or identical to solenoid arrangement10. As shown, solenoid arrangement 10′ includes solenoid valves 20 and22 including pressure switches 40 and 42 disposed substantially as shownand described hereinabove with respect to solenoid arrangement 10.Solenoid valve 24′ is substantially identical to solenoid valve 24 ofFIG. 1, however as shown, valve 24′ is disposed in a reverseconfiguration relative to valve 24. In this embodiment, conduits 30 and34 are respectively coupled to ports 244 and 242. Similarly, pressureswitch 44 and conduit 18 are respectively coupled to ports 243 and 241.In addition, rather than one of the ports (i.e. port 243 of valve 24)being vented, port 245 is plugged to prevent discharge of fluid duringnormal fluid flow. In this embodiment, the contacts of pressure switch44 remain in a first state (i.e. closed) as long as solenoid valve 24′is disposed in its energized state as shown. Pressure switch 44 changesstate only when solenoid valve 24′ is de-energized while solenoid valves20 and 22 remain energized. In such an event, fluid flowing throughconduit 34 will be coupled to the pressure switch 44 to thereby changeor open its contacts. A truth table showing the state of pressureswitches 40, 42 and 44 during individual de-energization of solenoidvalves 20, 22 and 24′ is shown in FIG. 4. Stack selector valve includingvalves 50 and 52, is disposed and operated substantially as describedhereinabove with respect to solenoid arrangement 10. In addition asshown, an optional pressure switch 56 may be coupled between valve 52and valve 14 to monitor and verify flow of fluid therebetween.

[0038] The voting solenoid arrangements 10 and 10′ of the presentinvention including the stack selector valve formed by valves 50, 52 andpressure switch 54, may be implemented in any convenient manner. Forexample the components thereof may be coupled to one another as shownand described herein, using suitable conduit or channel means such astubing fabricated from a flexible polymeric material, or from ametallic, material such as steel, copper, etc. In a preferredembodiment, the solenoid valves of the present invention are disposedwithin a unitary manifold (not shown), which incorporates the fluid flowpaths therein. The stack selector valve including valves 50 and 52 mayalso be disposed within the manifold if desired. Use of such a manifold,with the fluid pathways or conduits integrally disposed therein,advantageously serves to reduce installation and maintenance costrelative to the non-manifolded arrangements.

[0039] Referring now to FIG. 5, another alternate embodiment of thepresent invention is shown as voting solenoid arrangement 10″. It is inmany respects substantially similar or identical to solenoid arrangement10. As shown, solenoid arrangement 10″ includes solenoid valves 20, 22and 24 and including pressure switches 40, 42 and 44 disposedsubstantially as shown and described hereinabove with respect tosolenoid arrangement 10. Solenoid arrangement 10″ further includes abi-directional five-port valve 55 in place of stack selector valves 50and 52 (which are used in solenoid arrangement 10 and shown in FIG. 1).Valve 55 is typically included inside the manifold and functionssimilarly to valves 20, 22, 24 except that it is generally preferredthat it be manually operatable. In this embodiment, conduits 16 and 18are coupled to ports 264 and 262, respectively. Port 263 is coupledthrough conduit 38 to port 244 of solenoid valve 24. In addition, port261 is coupled to supply 12, while port 265 is vented. Further, pressureswitch 54″ is coupled to conduit 16. In the energized state valve 55connects supply 12 to conduit 16 and port 244 of solenoid valve 24through conduit 38 to conduit 18. In the de-energized state valve 55connects supply 12 directly to conduit 18 and vents conduit 16, whichopens pressure switch 54″. The artisan of ordinary skill will recognizethat solenoid arrangement 10″ functions substantially identically tothat of solenoid arrangement 10. This is further demonstrated by thetruth table showing the state of pressure switches 40, 42 and 44 duringindividual de-energization of solenoid valves 20, 22, and 24 forsolenoid arrangement 10″, which is identical to that of solenoidarrangement 10 (shown in FIG. 2).

[0040] For some commercial applications it is desirable to use the “2out of 3” voting solenoid arrangement of the present invention in atwo-way configuration rather than in a three-way configuration (solenoidarrangements 10, 10′ and 10″ are designed for a three-wayconfiguration). Referring now to FIGS. 6A and 6B, a two-way and athree-way configuration are contrasted. As shown, each of theconfigurations includes an input 12 (also previously referred to as afluid source and/or a fluid supply), a valve 14, an output 15 (shown asa vent in FIGS. 1 and 3) and a solenoid arrangement, referred to as 10Afor the three-way configuration and 10B for the two-way configuration.In each configuration input 12 may be thought of as making a ‘T-type’connection with output 15 and valve 14. As used herein, the principledifference between the two-way and three-way configurations is asfollows: In a three-way configuration, the ‘T-type’ connection generallyresides within solenoid arrangement 10A, which functions to selectivelycouple input 12 with output 15 and valve 14. Solenoid arrangement 10Acouples valve 14 to input 12 (effectively blocking output 15) whenenergized and couples valve 14 to output 15 (blocking input 12) whende-energized. In a two-way configuration, solenoid arrangement 10Bgenerally resides between the ‘T-type’ connection and output 15.Solenoid arrangement 10B functions essentially as a two-way valve thatselectively opens and closes upon actuation. When energized it closesthe connection to output 15 (i.e. interrupts fluid communication betweeninput 12 and output 15) allowing input 12 to pressurize valve 14. Whende-energized it opens the connection to output 15 (i.e. provides forfluid communication between input 12 and output 15), effectively‘shorting’ input 12 and releasing pressure from valve 14.

[0041] Referring now to FIG. 7, in yet another alternate embodiment, thepresent invention may be configured for two-way function and is shown asvoting solenoid arrangement 10″′. Solenoid arrangement 10″′ is similarto the previous embodiment (solenoid arrangement 10) in that it includesthree solenoids 20, 22 and 24 (preferably being of the kind having 5ports and bi-directional flow) and pressure switches 40, 42 and 44 whosefunction is described hereinabove with respect to FIG. 1. Solenoidarrangement 10″′ differs from solenoid arrangement 10 in that stackselector valves 52 and 54 are eliminated. Supply 12 is connecteddirectly to conduit 16, which is further connected to ports 201 and 225(through conduit 32) of valves 20 and 22, respectively. Conduit 16 isstill further connected (through conduit 36) to port 244 of valve 24. Inthis manner supply 12 is connected directly to each of the threesolenoids. Further, pressure switch 54″ is coupled to conduit 16. Stillfurther, it may be preferred for some applications for solenoid 10″′ toutilize hydraulic fluid rather than air.

[0042] Solenoid 10″′ is substantially similar to solenoid arrangement 10in that it functions in a “2 out of 3” manner, and therefore, mayprovide relatively high safety, relatively low spurious tripping and arelatively low installation cost. However, having a two-wayconfiguration, solenoid 10″′ simply de-couples supply 12 from output 15when all three solenoid valves 20, 22 and 24 are energized. As statedabove, conduit 16 simultaneously supplies fluid to valves 20, 22 and 24at ports 201, 225 and 244, respectively. Fluid at port 201 flows throughvalve 20 to port 202 and then through conduit 28 to port 221 of valve22. It then flows through valve 22 to port 222 and through conduit 30,pressurizing switch 42, to port 241 of valve 24 where it flows throughto port 242 and pressurized switch 44. Fluid at port 225 flows throughvalve 22 to port 224 and then through conduit 34 to port 245 of valve 24where it flows to port 244 and then through conduit 36 back to conduit16. Fluid at port 244 of valve 24 has the opposite flow direction asthat at port 225 of valve 22 described immediately above. As described,solenoid 10″′ does not provide for fluid communication between supply 12and output 15 when solenoid valves 20, 22 and 24 are energized, andtherefore may maintain the fluid pressure provided by supply 12.

[0043] In the event of a change of state of any single valve 20, 22 and24, such as in the event of a valve failure or valve test, solenoidarrangement 10″′ continues to hold the fluid pressure provided by supply12. For example, in the event that solenoid valve 20 is de-energized,fluid pressure at port 201 is diverted to port 204, thereby pressurizingswitch 40. Port 202 is diverted to port 203, which is vented, releasingthe pressure at switches 42 and 44, which are in fluid communicationwith port 202 (when valves 22 and 24 are energized as described above).The function of switches 40, 42 and 44 is substantially identical tothat of solenoid arrangement 10. This is further demonstrated by thefact that the truth table for solenoid arrangement 10″′ is identical tothat of solenoid arrangement 10 (as shown in FIG. 2). While switches 42and 44 are vented and fluid is diverted such that it pressurizes switch40, there is no fluid communication between supply 12 and output 15(typically a vent or an exhaust). Solenoid arrangement 10″′, therefore,continues to hold the pressure provided by supply 12. Likewise, and in asimilar manner, solenoid arrangement 10″′ holds pressure if onlysolenoid valve 22 or 24 are de-energized.

[0044] In the event that any two out of three or all three of solenoidvalves 20, 22 or 24 are de-energized, solenoid valve 10″′ provides forfluid communication between supply 12 and output 15. For example ifvalves 20 and 24 are de-energized, fluid at port 244 of valve 24 isdiverted to port 241 where it flows through conduit 30 to port 222 ofvalve 22. Fluid may then flow through valve 22 to port 221 and thenthrough conduit 28 to port 202 of valve 20. Fluid at port 202 isdiverted to port 203, which is coupled with output 15, thereby providingfluid communication between supply 12 and output 15. Likewise, and in asimilar manner, fluid communication is provided between supply 12 andoutput 15 if any other combination of two out of three or three outthree of valves 20, 22 and 24 are de-energized.

[0045] The foregoing description is intended primarily for purposes ofillustration. Although the invention has been shown and described withrespect to an exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omissions, and additions in the form and detail thereof may be madetherein without departing from the spirit and scope of the invention.

Having thus described the invention, what is claimed is:
 1. A binaryvoting solenoid arrangement adapted to selectively couple a fluid supplywith a fluid receiver, said voting solenoid arrangement comprising:first, second and third solenoid valves each having a plurality ofports; a plurality of inlet and outlet pathways each extending from arespective port of one of said solenoid valves to a port of another ofsaid solenoid valves, wherein said solenoid valves are disposed in fluidcommunication with one another; a by-pass valve having first and secondopen and closed positions, said by-pass valve being adapted toselectively couple the fluid source with the fluid receiver whilebypassing said first, second and third solenoid valves, said by-passvalve including a five port, four way by-pass valve; a single port ofsaid bypass valve being the fluid receiver; each of said first, second,and third solenoid valves and said by-pass valve being alternativelyactuatable between first and second open and closed positions; whereinactuation of at least any two of said first, second and third solenoidvalves alternately couples and de-couples the fluid supply with saidfluid receiver.
 2. The voting solenoid arrangement of claim 1 whereinsaid by-pass valve includes a pair of common ports which are selectivelycoupled in fluid communication with three other ports, said alternateactuation including alternately coupling said pair of common ports witha distinct two of said three other ports.
 3. The voting solenoidarrangement of claim 1 wherein said by-pass valve is manuallyoperatable.
 4. The voting solenoid arrangement of claim 1 wherein saidby-pass valve is included with said first, second and third solenoidvalves in a manifold.
 5. The voting solenoid arrangement of claim 1wherein actuation of said by-pass valve alternately couples andde-couples said fluid supply with the fluid receiver.
 6. The votingsolenoid arrangement of claim 1 wherein: a single port of said by-passvalve is coupled in fluid communication with the fluid supply; each ofsaid first and second solenoid valves are coupled with said by-passvalve such that each of said first and second solenoid valves are influid communication with the fluid supply when said by-pass valve is insaid first position; said second solenoid valve is coupled in fluidcommunication with said third solenoid valve; and said third solenoidvalve is coupled with said by-pass valve such that said third solenoidvalve is in fluid communication with the fluid receiver when saidby-pass valve is in said first position.
 7. The voting solenoidarrangement of claim 6 wherein: each of said first, second and thirdsolenoid valves further comprise a plurality of upstream ports and aplurality of downstream ports; said by-pass valve is coupled to anupstream port of each of said first and second solenoid valves; at leasttwo of said plurality of downstream ports of said second solenoid valveare respectively coupled in fluid communication along discrete pathwayswith at least two of said plurality of upstream ports of said thirdsolenoid valve; and a downstream port of said third solenoid valve iscoupled to said by-pass valve.
 8. The voting solenoid arrangement ofclaim 7 , wherein: said first, second and third solenoid valves eachcomprise five port, four way solenoid valves having a pair of commonports which are selectively coupled in fluid communication with threeother ports, said alternate actuation including alternately couplingsaid pair of common ports with a distinct two of said three other ports.9. The voting solenoid arrangement of claim 8 , wherein: said by-passvalve is coupled to one of said other ports of each of said first andsecond solenoid valves, each of said pair of common ports of said secondsolenoid valve are respectively coupled along discrete pathways with twoof said three other ports of said third solenoid valve; and one of saidcommon ports of said third solenoid valve is coupled to said by-passvalve.
 10. The voting solenoid arrangement of claim 1 , wherein saidfirst, second and third solenoid valves each comprise five port, fourway solenoid valves.
 11. The voting solenoid arrangement of claim 10 ,wherein said five port, four way solenoid valves further comprise a pairof common ports which are selectively coupled in fluid communicationwith three other ports, said alternate actuation including alternatelycoupling said pair of common ports with a distinct two of said threeother ports.
 12. The voting solenoid arrangement of claim 1 wherein thefluid comprises at least one of air and hydraulic fluid.
 13. The votingsolenoid arrangement of claim 1 , wherein the fluid is coupled betweenthe fluid supply and the fluid receiver when any two of said first,second and third solenoid valves are disposed in said first state. 14.The voting solenoid arrangement of claim 13 , wherein any one of saidfirst, second and third solenoid valves is adapted for being disposed insaid second state without de-coupling the fluid supply from the fluidreceiver.
 15. The voting solenoid arrangement of claim 1 , furthercomprising a plurality of pressure sensors operatively associated withsaid first, second and third solenoid valves and with said by-pass valveto indicate the state thereof.
 16. The voting solenoid arrangement ofclaim 15 , wherein said plurality of pressure sensors is adapted toindicate the state of each of said first, second and third solenoidvalves when the fluid supply is coupled to the fluid receiver.
 17. Thevoting solenoid arrangement of claim 15 , wherein said first, second andthird solenoid valves are adapted for being individually tested withoutde-coupling the fluid supply from the fluid receiver, said plurality ofpressure sensors being adapted to indicate the state of the individualsolenoid valve being tested.
 18. A binary voting solenoid arrangementadapted to selectively couple a fluid supply with a fluid receiver, saidvoting solenoid arrangement comprising: first, second and third solenoidvalves each including at least two common ports and three other ports,wherein said at least two common ports are selectively coupled in fluidcommunication with a distinct two of three other ports; a manuallyoperated by-pass valve having first and second open and closedpositions, said by-pass valve being adapted to selectively couple thefluid source with the fluid receiver while bypassing said first, secondand third solenoid valves, said by-pass valve including a five port,four way by-pass valve; a single port of said bypass valve being thefluid receiver; a single port of said by-pass valve being coupled influid communication with the fluid supply, each of said first and secondsolenoid valves being coupled with said by-pass valve such that each ofsaid first and second solenoid valves are in fluid communication withthe fluid supply when said by-pass valve is in said first position; saidsecond solenoid valve being coupled in fluid communication with saidthird solenoid valve; and said third solenoid valve being coupled withsaid by-pass valve such that said third solenoid valve is in fluidcommunication with the fluid receiver when said by-pass valve is in saidfirst position. each of said first, second and third solenoid valvesbeing alternatively actuatable between first and second open and closedpositions; wherein actuation of at least any two of said first, secondand third solenoid valves alternately couples and de-couples the fluidsupply with the fluid receiver.
 19. A two-way valve including a votingsolenoid arrangement adapted to selectively couple a fluid input and afluid output, said voting solenoid arrangement comprising: first,second, and third solenoid valves each having a plurality of ports; aplurality of inlet and outlet pathways each extending from a respectiveport of one of said solenoid valves to a port of another of saidsolenoid valves, wherein said solenoid valves are disposed in fluidcommunication with one another; at least one port of each of said first,second and third solenoid valves being the fluid output; each of saidfirst, second and third solenoid valves being alternatively actuatablebetween first and second open and closed positions; wherein actuation ofat least any two of said first, second and third solenoid valvesalternately couples and decouples the fluid input with said fluidoutput.
 20. The two-way valve of claim 19 wherein said fluid output is avent or drain.
 21. The two-way valve of claim 19 wherein said first,second and third solenoid valves each include five port, four waysolenoid valves.
 22. The two-way valve of claim 21 wherein said fiveport, four way solenoid valves further comprise a pair of common portswhich are selectively coupled in fluid communication with three otherports, said alternate actuation including alternately coupling saidfirst pair of common ports with a distinct two of said three otherports.
 23. The two-way valve of claim 19 wherein: said first, second andthird solenoid valves are each coupled in fluid communication with thefluid input; said first solenoid valve is coupled in fluid communicationwith said second solenoid valve; and said second solenoid valve iscoupled in fluid communication with said third solenoid valve.
 24. Thetwo-way valve of claim 23 wherein: said first, second and third solenoidvalves each comprise five port, four way solenoid valves having a pairof common ports which are selectively coupled in fluid communicationwith three other ports, said alternate actuation including alternatelycoupling said first pair of common ports with a distinct two of saidthree other ports.
 25. The two-way valve of claim 24 wherein: the fluidinput is coupled to one of said other ports of each of said first andsecond solenoid valves; the fluid input is coupled to one of said pairof common ports of said third solenoid valve; each of said pair ofcommon ports of said second solenoid valve are respectively coupledalong discrete pathways with two of said three other ports of said thirdsolenoid valve; and at least one of said other ports of each of saidfirst, second and third solenoid valves are coupled with the fluidoutput.
 26. The two-way valve of claim 19 wherein said voting solenoidarrangement is configured such that any one of said first, second andthird solenoid valves may be actuated without selectively coupling andde-coupling the fluid input with the fluid output.
 27. The two-way valveof claim 19 wherein said fluid comprises hydraulic fluid or air.
 28. Thetwo-way valve of claim 19 further comprising a plurality of pressuresensors operatively associated with said first, second and thirdsolenoid valves to indicate the state thereof.
 29. The two-way valve ofclaim 28 wherein said first, second and third solenoid valves areadapted for being individually tested without de-coupling the fluidinput from the fluid output, said plurality of pressure sensors beingadapted to indicate the state of the individual solenoid valve beingtested.
 30. A two-way valve comprising: first, second and third solenoidvalves each including at least two common ports and three other ports,wherein said at least two common ports are selectively coupled in fluidcommunication with a distinct two of three other ports; at least one ofsaid other ports of each of said first and second solenoid valves beingin fluid communication with a fluid input; at least one of said pair ofcommon ports of said third solenoid valve being in fluid communicationwith a fluid input; at least one of said three other ports of each ofsaid first, second and third solenoid valves being in fluidcommunication with a fluid output; wherein said first solenoid valve isin fluid communication with said second solenoid valve; wherein at leasttwo of said common ports of said second solenoid valve are respectivelycoupled along discrete pathways with two of said three other ports ofsaid third solenoid valve; wherein each of said first, second and thirdsolenoid valves are alternatively actuatable between open and closedpositions; and wherein actuation of at least any two of said first,second and third solenoid valves alternately couples and decouples thefluid input and fluid output of said two-way valve.
 31. A method forselectively coupling a fluid supply with a fluid receiver, the methodcomprising: providing first, second and third solenoid valves eachhaving a plurality of ports, and each being alternately actuatablebetween open and closed positions; and providing a plurality of inletand outlet pathways each extending from a respective port of one of saidsolenoid valves to a port of another of said solenoid valves, whereinsaid solenoid valves are disposed in fluid communication with oneanother, said first solenoid valve in fluid communication with saidsecond solenoid valve and said second solenoid valve in fluidcommunication with said third solenoid valve; providing a five port,four way by-pass valve; and coupling one port of said by-pass valve tothe fluid supply and another port of said bypass valve to the fluidreceiver such that actuation of said by-pass valve selectively couplesthe fluid source with the fluid receiver while bypassing said first,second and third solenoid valves, wherein actuation of any two of saidfirst, second and third solenoid valves alternately couples andde-couples the fluid supply with the fluid receiver.
 32. A method forfabricating a two-way valve for selectively coupling a fluid input witha fluid output, the method comprising: providing first, second and thirdsolenoid valves each having a plurality of ports, and each beingalternately actuatable between open and closed positions; providing aplurality of inlet and outlet pathways each extending from a respectiveport of one of said solenoid valves to a port of another of saidsolenoid valves, wherein said solenoid valves are disposed in fluidcommunication with one another, said first solenoid valve in fluidcommunication with said second solenoid valve and said second solenoidvalve in fluid communication with said third solenoid valve; couplingthe fluid input to at least one port of each of said first, second andthird solenoid valves; and coupling the fluid output to at least oneport of each of said first, second and third solenoid valves; whereinactuation of any two of said first, second and third solenoid valvesalternately couples and de-couples the fluid supply with the fluidreceiver.